espidf sgp30

### 关于ESP-IDF框架中使用SGP30传感器的信息 在ESP-IDF框架下使用SGP30传感器涉及到初始化I2C总线以及配置SGP30设备。为了实现这一目标，通常会利用`driver/i2c.h`库来管理I2C通信，并调用特定API函数完成对SGP30的操作。 下面是一个简单的例子展示如何设置并读取来自SGP30的数据： ```c #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "esp_system.h" #include "nvs_flash.h" #include "driver/i2c.h" #define I2C_MASTER_SCL_IO 22 /*!< GPIO number used for I2C master clock */ #define I2C_MASTER_SDA_IO 21 /*!< GPIO number used for I2C master data */ #define I2C_MASTER_NUM I2C_NUM_1 /*!< I2C port number, the number of I2C interfaces in ESP32 is two, select one from it*/ #define I2C_MASTER_TX_BUF_DISABLE 0 /*!< I2C master do not need buffer */ #define I2C_MASTER_RX_BUF_DISABLE 0 /*!< I2C master do not need buffer */ #define I2C_MASTER_FREQ_HZ 100000 /*!< I2C master clock frequency */ // SGP30 specific definitions #define SGP30_I2C_ADDRESS 0x58 /*!< Default address for SGP30 on I2C bus */ #define CMD_INIT_AIR_QUALITY {0x20, 0x03} /*!< Command to initialize air quality measurement mode */ #define CMD_MEASURE {0x20, 0x08} /*!< Command to measure CO2eq and TVOC levels */ static esp_err_t i2c_master_init(void){ int i2c_master_port = I2C_MASTER_NUM; /// Configure parameters of an I2C transaction i2c_config_t conf = { .mode = I2C_MODE_MASTER, .sda_io_num = I2C_MASTER_SDA_IO, .scl_io_num = I2C_MASTER_SCL_IO, .sda_pullup_en = GPIO_PULLUP_ENABLE, .scl_pullup_en = GPIO_PULLUP_ENABLE, .master.clk_speed = I2C_MASTER_FREQ_HZ, }; // Install and start I2C driver i2c_param_config(i2c_master_port, &conf); return i2c_driver_install(i2c_master_port, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0); } void app_main(void) { // Initialize NVS (Non-Volatile Storage) esp_err_t ret = nvs_flash_init(); if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) { // NVS partition was truncated and needs to be erased // Retry nvs_flash_init ESP_ERROR_CHECK(nvs_flash_erase()); ret = nvs_flash_init(); } ESP_ERROR_CHECK(ret); // Initialize I2C Master Interface i2c_master_init(); uint8_t cmd[2]; memcpy(cmd, CMD_INIT_AIR_QUALITY, sizeof(CMD_INIT_AIR_QUALITY)); // Send initialization command to SGP30 over I2C i2c_cmd_handle_t tx_cmd = i2c_cmd_link_create(); i2c_master_start(tx_cmd); i2c_master_write_byte(tx_cmd, (SGP30_I2C_ADDRESS << 1) | WRITE_BIT, ACK_CHECK_EN); i2c_master_write(tx_cmd, cmd, 2, true); i2c_master_stop(tx_cmd); i2c_master_cmd_begin(I2C_MASTER_NUM, tx_cmd, pdMS_TO_TICKS(1000)); i2c_cmd_link_delete(tx_cmd); vTaskDelay(pdMS_TO_TICKS(10)); // Wait a bit before starting measurements while(true){ // Prepare measurement request memcpy(cmd, CMD_MEASURE, sizeof(CMD_MEASURE)); // Start new transaction link tx_cmd = i2c_cmd_link_create(); // Write command bytes followed by reading response back into `data` i2c_master_start(tx_cmd); i2c_master_write_byte(tx_cmd, (SGP30_I2C_ADDRESS << 1)|WRITE_BIT ,ACK_CHECK_EN ); i2c_master_write(tx_cmd,cmd,sizeof(CMD_MEASURE),true); i2c_master_stop(tx_cmd); i2c_master_cmd_begin(I2C_MASTER_NUM,tx_cmd,pdMS_TO_TICKS(1000)); i2c_cmd_link_delete(tx_cmd); uint8_t data[6]; // Buffer holding received values i2c_cmd_handle_t rx_cmd=i2c_cmd_link_create(); i2c_master_start(rx_cmd); i2c_master_write_byte(rx_cmd,(SGP30_I2C_ADDRESS<<1)|READ_BIT,ACK_CHECK_DIS); i2c_master_read(rx_cmd,data,6,true); // Read six bytes including CRC checksums i2c_master_stop(rx_cmd); i2c_master_cmd_begin(I2C_MASTER_NUM,rx_cmd,pdMS_TO_TICKS(1000)); i2c_cmd_link_delete(rx_cmd); // Process raw readings here... printf("CO2 equivalent: %u ppm\n", ((uint16_t)data[0]<<8)|(uint16_t)data[1]); printf("TVOC concentration: %u ppb\n",((uint16_t)data[3]<<8)|(uint16_t)data[4]); vTaskDelay(pdMS_TO_TICKS(1000));// Delay between samples } } ``` 此代码片段展示了如何创建一个基于ESP-IDF的应用程序，该应用程序能够与SGP30空气质量传感器交互以获取二氧化碳当量（CO₂ eq）和挥发性有机化合物浓度（TVOC）。这段代码首先设置了必要的硬件资源——特别是用于连接到SGP30的I2C接口；接着发送命令给传感器使其进入工作状态；最后定期查询最新的测量结果并将它们打印出来[^1]。